Surgical tool with flex circuit ultrasound sensor

ABSTRACT

A medical instrument includes a printed ultrasound sensor, a surface, at least one non-conductive material, and at least one pair of contacts. The ultrasound sensor includes an array of ultrasound transducers printed on a non-conductive surface of the medical instrument. The medical instrument contains multiple conductive and nonconductive layers. The at least one pair of contacts are electrically coupled to the ultrasound sensor and operably coupled to the conductive layer, the conductive layer coupled to a measurement device, which converts electrical signals from the ultrasound sensor into images displayed on a display unit. The location of the medical instrument can be visualized in real time on the display unit.

CROSS-REFERENCE TO RELATED APPLICATIONS

This application is a continuation of U.S. patent application Ser. No.15/063,654, filed on Mar. 8, 2016. The entire disclosures of all of theforegoing applications are incorporated by reference herein.

BACKGROUND Technical Field

The present disclosure relates to a medical instrument including anultrasound sensor. More particularly, the present disclosure relates tosystems and methods that confirm a location of a medical instrumenthaving an ultrasound transducer.

Discussion of Related Art

Electromagnetic navigation (EMN) has helped expand the possibilities oftreatment to internal organs and diagnosis of diseases. EMN relies onnon-invasive imaging technologies, such as computed tomography (CT)scanning, magnetic resonance imaging (MRI), or fluoroscopictechnologies. These images may be registered to a location of a patientwithin a generated magnetic field, and as a result the location of asensor placed in that field can be identified with reference to theimages. As a result, EMN in combination with these non-invasive imagingtechnologies is used to identify a location of a target and to helpclinicians navigate inside of the patient's body to the target.

In one particular example of currently marketed systems in the area oflocating the position of medical instruments in a patient's airway, asensor is placed at the end of a probe referred to as a locatable guideand passed through an extended working channel (EWC) or catheter, andthe combination is inserted into the working channel of a bronchoscope.The EWC and probe with the sensor is then navigated to the target withinthe patient. Once the target is reached, the locatable guide (i.e.,sensor and probe) can be removed and one or more instruments, includingbiopsy needles, biopsy brushes, ablation catheters, and the like can bepassed through the working channel and EWC to obtain samples and/ortreat the target. At this point, however, because the locatable guidewith the sensor has been removed, the exact location of a distal end ofthe EWC, and by extension any instrument which might be passed therethrough is not precisely known. In addition, the precise location withinthe target tissue is not entirely clear.

Images generated by the non-invasive imaging technologies describedabove do not provide the resolution of live video imaging. To achievelive video, a clinician may utilize the features of an endoscope.However, an endoscope is limited by its size and as a result cannot benavigated to the pleura boundaries of the lungs and other very narrowpassageways as is possible with tools typically utilized in EMN. Analternative is a visualization instrument that is inserted through theEWC and working channel of the endoscope, which can be sized to reachareas such as the pleura boundaries.

As with the locatable guide, however, once the visualization instrumentis removed the location of the distal end of the EWC is unclear. Onetechnique that is used is the placement of one or more markers into thetissue near the target and the use of fluoroscopy to confirm location ofthe EWC and the markers, and any subsequent instruments passed throughthe EWC. Due to the small diameter of the EWC, simultaneous insertion ofmore than one instrument may be impractical. Thus, repeated insertionsand removals of instruments for visualization, diagnosis, and surgeriesare necessitated. Such repeated insertions and removals lengthendiagnostic or surgical time and efforts, and increase costs on patientscorrespondingly. Thus, it is desirous to make a fewer insertion and/orremoval of instruments to shorten times necessary for diagnosis andsurgeries while at the same time increasing the certainty of thelocation of the EWC and instruments passed through the EWC, includingimaging modalities.

SUMMARY

Provided in accordance with the present disclosure is a medicalinstrument including a printed ultrasound sensor. In particular, themedical instrument includes a conductive layer printed circumferentiallyaround at least a portion of a catheter and a nonconductive layerprinted on top of the conductive layer. An ultrasound sensor is printedon a distal portion of the nonconductive layer. The ultrasound sensor isadapted to transmit and receive signals. At least one pair of vias areformed in the conductive layer and nonconductive layer and enable anelectrical connection between the ultrasound sensor and the conductivelayer. In embodiments, the conductive layer is copper, silver, gold,conductive alloys, or conductive polymer. The medical instrument alsoincludes a connector formed on a proximal end of the catheter forconnection to an ultrasound image resolution device.

According to aspects of the disclosure, the medical instrument alsoincludes an electromagnetic sensor disposed on a distal portion of thecatheter. The medical instrument further includes a base non-conductivelayer on the distal portion of the medical instrument on which theelectromagnetic sensor is printed.

In embodiments, the ultrasound sensor includes an array of ultrasoundtransducers. The ultrasound transducers are formed of piezoelectricmaterial. In embodiments, the ultrasound transducers are made at leastin part of silicon diaphragms, wherein the piezoelectric material isprinted on the silicon diaphragms. The piezoelectric material may beperovskite phase lead zirconate titanate (PZT), quartz, lead titanate,barium titanate, or polyvinylidene fluoride (PVDF). In embodiments, thearray of ultrasound transducers are printed in parallel rows ofultrasound transducers.

In another embodiment, the medical instrument is an extended workingchannel, a biopsy forceps, a biopsy brush, a biopsy needle, or amicrowave ablation probe. In further embodiments, the medical instrumentincludes an outer surface formed of ethylene tetrafluoroethylene (ETFE),polytetrafluoroethylene (PTFE), polyimide, or non-conductive polymer.

According to aspects of the disclosure, the ultrasound sensor,conductive layer, and the non-conductive layer are printed usingdrop-on-demand (DOD) or ink-jet printing. Additionally, theelectromagnetic sensor is printed on a distal portion of the medicalinstrument.

In another embodiment, the electromagnetic sensor includes at least onepair of contacts electrically connected to the electromagnetic sensor,wherein at least one pair of contacts is coupled to the conductivelayer. According to aspects of the disclosure, the conductive layer isconnectable to a measurement device configured to sense an inducedelectrical signal based on a magnetic flux change of an electromagneticfield, wherein a location of the medical instrument in a coordinatesystem of the electromagnetic field is identified based on the inducedelectrical signal in the electromagnetic sensor.

BRIEF DESCRIPTION OF THE DRAWINGS

Objects and features of the presently disclosed systems and methods willbecome apparent to those of ordinary skill in the art when descriptionsof various embodiments are read with reference to the accompanyingdrawings, of which:

FIG. 1 is a perspective schematic view of a system for identifying alocation of a medical instrument in accordance with an embodiment of thepresent disclosure;

FIG. 2A is a schematic view of a catheter guide assembly and medicalinstrument in accordance with the present disclosure;

FIG. 2B is an enlarged view of one embodiment of the indicated area ofdetail of FIG. 2A;

2C is an enlarged view of another embodiment of the indicated area ofdetail of FIG. 2A;

2D is an enlarged view of yet another embodiment of the indicated areaof detail of FIG. 2A;

FIG. 3 depicts a partial perspective view, which illustrates oneembodiment of an ultrasound sensor printed at the distal portion of amedical instrument in accordance with an embodiment of the presentdisclosure;

FIG. 4 is a partial perspective side view of an illustrative design of aproximal portion of a medical instrument around which a series ofconductive and nonconductive layers are printed;

FIGS. 5A-5D are partial side views of a plurality of medical instrumentsin accordance with an embodiment of the present disclosure;

FIG. 6 is schematic illustration of a printer that prints an ultrasoundsensor on a surface of a medical instrument in accordance with anembodiment of the present disclosure; and

FIG. 7 is a flowchart of a method for printing an ultrasound sensor on amedical instrument in accordance with an embodiment of the presentdisclosure.

DETAILED DESCRIPTION

The present disclosure is related to medical instruments, systems andmethods for identifying a location of medical instruments by using anultrasound sensor. The ultrasound sensor may be printed directly on orseparately fabricated and then affixed to the medical instruments. Sincethe ultrasound sensor may be inserted inside of patient's body withmedical instruments, the location of the medical instrument can bedetermined in real-time. Further, the sensor may work in conjunctionwith and/or supplement other imaging modalities. Due to the small sizeof the ultrasound sensor, medical instruments may incorporate the sensorwithin the medical instruments, to facilitate continuous navigation.Although the present disclosure will be described in terms of specificillustrative embodiments, it will be readily apparent to those skilledin this art that various modifications, rearrangements, andsubstitutions may be made without departing from the spirit of thepresent disclosure. The scope of the present disclosure is defined bythe claims appended to this disclosure.

As used herein, the term “distal” refers to the portion that is beingdescribed which is further from a user, while the term “proximal” refersto the portion that is being described which is closer to a user.Further, to the extent consistent, any of the aspects and featuresdetailed herein may be used in conjunction with any or all of the otheraspects and features detailed herein.

FIG. 1 illustrates one illustrative embodiment of a system and methodfor identifying a location of medical instruments in an electromagneticfield. In particular, an electromagnetic navigation (EMN) system 100,which is configured to utilize CT, MRI, or fluoroscopic images, isshown. One such EMN system may be the ELECTROMAGNETIC NAVIGATIONBRONCHOSCOPY® system currently sold by Medtronic Inc. The EMN system 100includes a catheter guide assembly 110, a bronchoscope 115, a computingdevice 120, a monitoring device 130, an electromagnetic (EM) board 145,a tracking device 160, and reference sensors 170. The bronchoscope 115is operatively coupled to the computing device 120 and the monitoringdevice 130 via a wired connection (as shown in FIG. 1) or wirelessconnection (not shown).

FIG. 2A illustrates a schematic illustration of the catheter guideassembly 110 of FIG. 1. The catheter guide assembly 110 includes acontrol handle 210, which enables advancement and steering of the distalend 250 of the catheter guide assembly 110. The catheter guide assembly110 may include a catheter 270 inserted in the EWC 230, as shown in FIG.2B, a locatable guide catheter (LG) 290 inserted in the EWC 230, asshown in FIG. 2C, or a medical instrument 280 inserted in the EWC 230,as shown in FIG. 2D. The catheter 270 may further be configured toreceive a medical instrument 280.

In embodiments, the EM sensor 262 can be directly integrated into thedistal end of the catheter 270, LG 290, or the EWC 230, as depicted inFIGS. 2B-2D, respectively. In all three embodiments shown in FIGS.2B-2D, the catheter guide assembly 110 contains an ultrasound sensor(US) 260 at its distal end. Alternatively, in some embodiments, the USsensor 260 may be integrated into the distal end of the catheter 270 ordirectly on the medical instrument 280. A locking mechanism 225 maysecure the catheter 270, the LG 220, or the medical instrument 280 tothe EWC 230. The locking mechanism 225 allows a user to know therotational orientation of the catheter 270, the LG 220, or the medicalinstrument 280 in addition to its 3-dimensional position. Catheter guideassemblies usable with the instant disclosure may be currently marketedand sold by Medtronic Inc. under the name SUPERDIMENSION® Procedure Kitsand EDGE™ Procedure Kits.

For a more detailed description of the catheter guide assemblies,reference is made to commonly-owned U.S. Patent Application PublicationNumber 2014/0046315 filed on Mar. 15, 2013, by Ladtkow et al. and U.S.Pat. No. 7,233,820, the entire contents of which are incorporated inthis disclosure by reference. As will be described in greater detailbelow, the EM sensor 262 on the distal portion of the LG 290 or EWC 230senses the electromagnetic field, and is used to identify the locationof the LG 290 or EWC 230 in the electromagnetic field, and the US sensor260 may be used to image the target and confirm the position of the EWC230, LG 290, and/or the medical instrument 280.

In use, the bronchoscope 115 is inserted into the mouth or through anincision of a patient 150 to capture images of the internal organ. Inone embodiment of the EMN system 100, inserted into the bronchoscope 115is a catheter guide assembly 110 for achieving an access to the lung ofthe patient 150. The catheter guide assembly 110 may include an extendedworking channel (EWC) 230 into which a catheter 270 or LG 290 with theEM sensor 262 at its distal portion is inserted. Alternatively, the EWC230 may have an EM sensor 262 integrated at its distal portion. The EMsensor 262 is used to navigate the EWC 230 through the lung described ingreater detail below. Additionally, an US sensor 260 may be integratedat a distal portion of the EWC 230 (as shown in FIGS. 2B-2D) and/or thecatheter 270 (not shown) and is used to provide differential imaginginformation of the surrounding tissue.

In an alternative embodiment, instead of a bronchoscope 115 inserted viaa natural orifice, the catheter guide assembly 110 is inserted into thepatient 150 via an incision. The catheter guide assembly 110 includingthe EWC 230 may be inserted through the incision to navigate any luminalnetwork including the airways of a lung and a cardiac luminal network.

The computing device 120, such as, a laptop, desktop, tablet, or othersimilar computing device, includes a display 122, one or more processors124, memory 126, a network card 128, and an input device 129. The EMNsystem 100 may also include multiple computing devices, wherein theseparate computing devices are employed for planning, treatment,visualization, and other aspects of assisting clinicians in a mannersuitable for medical operations. The display 122 may be touch-sensitiveand/or voice-activated, enabling the display 122 to serve as both inputand output devices. The display 122 may display two dimensional (2D)images or a three dimensional (3D) model of an internal organ, such asthe lung, prostate, kidney, colon, liver, etc., to locate and identify aportion of the internal organ that displays symptoms of diseases.

The display 122 may further display options to select, add, and remove atarget to be treated and settable items for the visualization of theinternal organ. In an aspect, the display 122 may also display thelocation of the catheter guide assembly 110 in the electromagnetic fieldbased on the 2D images or 3D model of the internal organ. In anotheraspect, the display 122 may also display a live ultrasound imagecaptured by the US sensor 260. This live ultrasound image may besuperimposed over the 2D images or 3D model of the organs or over avirtual bronchoscopy image, or over a fluoroscopy image, or it may bedisplayed in a side-by-side configuration. In another embodiment, aseparate display 122 may be used to display the ultrasound image.

The one or more processors 124 execute computer-executable instructions.The processors 124 may perform image-processing functions so that the 3Dmodel of the internal organ and/or the ultrasound image can be displayedon the display 122. In embodiments, the computing device 120 may furtherinclude a separate graphic accelerator (not shown) that performs onlythe image-processing functions so that the one or more processors 124may be available for other programs. The memory 126 stores data andprograms. For example, data may be image data for the 3D model,ultrasound imaging, or any other related data such as patients' medicalrecords, prescriptions and/or history of the patient's diseases.

One type of program stored in the memory 126 is a 3D model and pathwayplanning software module (planning software). An example of the 3D modelgeneration and pathway planning software may be the EMN planningsoftware currently sold by Medtronic Inc. When image data of a patient,which is typically in digital imaging and communications in medicine(DICOM) format, from for example a CT image data set (or an image dataset by other imaging modality) is imported into the planning software, a3D model of the internal organ is generated. In an aspect, imaging maybe done by CT imaging, magnetic resonance imaging (MRI), functional MRI,X-ray, and/or any other imaging modalities. To generate the 3D model,the planning software employs segmentation, surface rendering, and/orvolume rendering. The planning software then allows for the 3D model tobe sliced or manipulated into a number of different views includingaxial, coronal, and sagittal views that are commonly used to review theoriginal image data. These different views allow the user to review allof the image data and identify potential targets in the images.

Once a target is identified, the software enters into a pathway planningmodule. The pathway planning module develops a pathway plan to achieveaccess to the targets and the pathway plan pin-points the location andidentifies the coordinates of the target such that they can be arrivedat using the EMN system 100, and particularly the catheter guideassembly 110 together with the EWC 230 and the LG 290,. The pathwayplanning module guides a clinician through a series of steps to developa pathway plan for export and later use during navigation to the targetin the patient 150. The term, clinician, may include doctor, surgeon,nurse, medical assistant, or any user of the pathway planning moduleinvolved in planning, performing, monitoring and/or supervising amedical procedure.

Details of these processes and the pathway planning module can be foundin U.S. Patent Application Publication Number 2014/0281961 filed byMedtronic Inc. on Jun. 21, 2013, and entitled “Pathway Planning Systemand Method,” the entire contents of which are incorporated in thisdisclosure by reference. Such pathway planning modules permit cliniciansto view individual slices of the CT image data set and to identify oneor more targets. These targets may be, for example, lesions or thelocation of a nerve which affects the actions of tissue where thedisease has rendered the internal organ's function compromised.

The memory 126 may store navigation and procedure software whichinterfaces with the EMN system 100 to provide guidance to the clinicianand provide a representation of the planned pathway on the 3D model and2D images derived from the 3D model. An example of such navigationsoftware is the ILOGIC® navigation and procedure suite sold byMedtronic, Inc. In practice, the location of the patient 150 in the EMfield generated by the EM field generating device 145 must be registeredto the 3D model and the 2D images derived from the 3D model. Suchregistration may be manual or automatic and is described in detail andcommonly assigned U.S. patent application Ser. No. 14/753,288 entitled“System and method for navigating within the lung,” the entire contentsof which are incorporated in this disclosure by reference.

As shown in FIG. 1, the patient surface or bed 140 is configured toprovide a flat surface for the patient to lie down and includes an EMfield generating device 145. When the patient 150 lies down on the EMboard 145, the EM field generating device in the EM board 145 generatesan EM field sufficient to surround a portion of the patient 150. The EMsensor 262 at the end of the LG 290 is used to determine the location ofthe distal end of the LG 290 and therewith the EWC 230 within thepatient. In an aspect, a separate EM sensor 262 may be located at thedistal end of the EWC 230 and therewith the exact location of the EWC230 in the EM field generated by the EM field generating device 145 canbe identified within the patient 150.

In yet another aspect, the EM board 145 may be configured to beoperatively coupled with the reference sensors 170 which are located onthe chest of the patient 150. The reference sensors 170 move upfollowing the chest while the patient 150 is inhaling and move downfollowing the chest while the patient 150 is exhaling. The movement ofthe chest of the patient 150 in the EM field is captured by thereference sensors 170 and transmitted to the tracking device 160 so thatthe breathing pattern of the patient 150 may be recognized. The trackingdevice 160 also receives the output of the EM sensor 262, combines bothoutputs, and compensates the breathing pattern for the location of theEM sensor 262. In this way, the location identified by the EM sensor 262may be compensated for such that the compensated location of the EMsensor 262 may be synchronized with the 3D model of the internal organ.As noted above, however, the use of an LG 290 with an EM sensor 262 atits distal end 250 can result in challenges surrounding instrumentswaps, loss of location information, and a general prolongation of thetime needed for a procedure. To alleviate these issues, the EM sensor262 may be printed directly on the distal portion of a medicalinstrument 280 or the EWC 230 as described in U.S. Provisional PatentApplication No. 62/170,383 filed by Medtronic Inc. on Jun. 3, 2015, andentitled “Medical Instrument with Sensor for use in a System and Methodfor Electromagnetic Navigation,” the entire contents of which areincorporated in this disclosure by reference. Additionally, a US sensor260 may be printed directly on the distal portion of a medicalinstrument 280, catheter 270, and/or EWC 230. When used in conjunctionwith the EM sensor 262, the US sensor 260 improves accuracy andprecision when navigating to a target tissue by providing real timeimaging of the distal end of the medical instrument 280, catheter 270,and/or EWC 230.

FIG. 3 depicts an embodiment of an US sensor 260 printed on aninstrument 300. The instrument 300 may be an EWC 230, a catheter 270, amedical instrument 280, a biopsy instrument, an ablation instrument, amonopolar or bipolar electrosurgical instrument, a marking instrument,or a needle, in short any instrument capable of being inserted into theluminal network (e.g., the airways or vasculature of a patient). In oneembodiment the instrument 300 is sized to pass through the EWC 230.Alternatively, the instrument 300 may be the EWC 230. Other exemplaryinstruments 300 are shown in FIGS. 5A-5D, depicting biopsy forceps 570,a biopsy brush 575, a biopsy needle 580, and a microwave ablation probe585, each having an US sensor 260 applied by the methods of the presentdisclosure. The US sensor 260 can provide ultrasound imaging of tissueat the distal end of instrument 300. When used in conjunction with an EMsensor 262, a user is able to identify the location of the instrument300 (through the EM sensor 262) and obtain a visual image of the preciselocation of the instrument 300 (through the US sensor 260). Any numberof combinations for the location of the US sensor 260 and EM sensor 262are envisioned. For example, some of which have been discussed above,the US sensor 260 may be located on the EWC 230 and the EM sensor 262 onthe instrument 300, or the US sensor 260 may be located on theinstrument 300 and the EM sensor 262 on the EWC 230. Alternatively, boththe US sensor 260 and the EM sensor 262 may be located on either the EWC230 or the instrument 300.

As will be described in greater detail below, the distal portion of theinstrument 300 may be made of or covered by Ethylene tetrafluoroethylene(ETFE), Polytetrafluoroethylene (PTFE), polyimide, or another suitablematerial to form a non-conductive base for the US sensor 260. If thedistal portion of the instrument 300 is not covered or made of anon-conductive material, a non-conductive material may be applied to thedistal portion first to form an insulating base for the US sensor 260.In embodiments, instrument 300 may comprise a hollow tube consisting ofan inner PTFE liner. The PTFE liner provides lubricity for easy slidingof tools down the center of the instrument 300. In one embodiment, theEM sensor 262 is printed directly on the PTFE layer. Radially outward ofthe PTFE layer is a wire braid layer (not shown). The wire braid helpsprovide structural integrity and torquability to allow for easymaneuverability of the instrument 300. The final layer is a thermalplastic layer which, through a heat process, bonds all three layerstogether to provide durability.

With respect to the US sensor 260 depicted in FIG. 3, the US sensor 260may be printed in an array. Although FIG. 3 depicts the US sensor 260printed in perpendicular rows, other configurations are envisioned. Forexample, the US sensor 260 may be printed in non-overlapping parallelrows (as depicted in FIGS. 2B-2D) or in non-perpendicular rows. The USsensor 260 is printed from piezoelectric material. In embodiments, an EMsensor 262 (shown in FIGS. 2B-D) is also printed on the instrument 300adjacent to the US sensor 260. PZT is a preferred material due to itsstrong mechanical to electrical coupling. The US sensor 260 may befabricated and printed on the medical instrument 300 using knownmicroelectromechanical system (MEMS) and/or nanoelectromechanical system(NEMS) techniques. In one embodiment, the US sensor 260 includes anarray of clamped silicon diaphragms (not shown), which are a commoncomponent of US sensors. In particular, a thin layer of piezoelectricmaterial, sandwiched between two electrodes, is printed on the silicondiaphragms.

In embodiments, the radius of the electrodes is smaller than the radiusof the diaphragm. When an AC driving signal is applied between theelectrodes, the resulting strain on the piezoelectric material vibratesthe structure and diaphragm sending ultrasonic pressure waves into itssurroundings. Alternatively, the US sensor 260 may be exposed toultrasonic pressure waves from its surrounding environment, and thesewaves are translated into electrical signals.

In embodiments, the US sensor 260 may be printed in an array of USsensors coupled together using known printing techniques, such asdrop-on-demand (DOD) or ink-jet printing. The US sensor 260 and the EMsensor 262 may be printed adjacent each other or they may be printed inlayers. Specifically, the EM sensor 262 is first printed on theinstrument 300, a non-conductive material is than applied over the EMsensor 262, and the US sensor 260 is printed on the non-conductivematerial. It is envisioned that any number of layers and/or combinationof sensors may be printed on the instrument 300. Each sensor may have adifferent configuration or location, e.g., a different orientation, adifferent length L, and a different distance from the distal end of theinstrument 300.

In accordance with the present disclosure, US sensor 260 may be printeddirectly onto the instrument 300. That is, during the manufacture of theinstrument 300, one of the processing steps is to apply one or moreconductive inks, piezoelectric material, or other materials to theinstrument 300. This printing may be performed by a number of processesincluding ink jet printing, flexographic printing, vapor deposition,etching, and others known to those of skill in the art without departingfrom the scope of the present disclosure. The US sensor 260 may have athickness of about 0.01 to about 0.05 millimeter (mm) so that the sensorcan be printed on an instrument 300 without appreciably increasing itsdimensions. In accordance with one embodiment, a final non-conductivelayer covers the US sensor 260, thereby protecting the top layer of theUS sensor 260. In some embodiments, the non-conductive material may beKapton, ETFE, PTFE, non-conductive polymer, or polyimide.

As depicted in FIG. 3, the US sensor 260 contains vias 302, 304connected to the terminals of US sensor 260. In embodiments, each via iselectrically coupled to a different conductive layer on the proximalportion of the instrument 300, as shown in more detail in FIG. 4.Although not shown, EM sensor 262 may also contain one or morerespective vias.

FIG. 4 depicts an embodiment of a proximal portion of an instrument 300and the various layers of conductive and/or nonconductive materialprinted directly onto the instrument. FIG. 4 is not drawn to scale andis meant for illustrative purposes only. Each layer of conductive and/ornonconductive material may range in thickness from 9 microns to 0.05millimeters (mm).

As described above, the EM sensor 262 and US sensor 260 printed on thedistal portion of instrument 300. On the proximal portion of theinstrument 300, nonconductive layers 400 and conductive layers 402, 404,406, 408 are printed directly on the PTFE layer in layers in alternatingfashion. In other words, a base nonconductive layer 400 is printed ontop of the PTFE layer followed by a conductive layer 402 printed on topof the base nonconductive layer. Another nonconductive layer is thenprinted on top of conductive layer 402 and another conductive layer 404is printed on top of the nonconductive layer. This process is thenrepeated until a desired number of nonconductive and conductive layersare achieved. In embodiments, the final layer is a nonconductive layerand a thermal plastic layer is then placed on top of the finalnonconductive layer. The embodiment shown in FIG. 4 illustrates a totalof four conductive layers 402, 404, 406, 408 and four nonconductivelayers 400. A final nonconductive layer (not shown) may be printed onthe final conductive layer 408. In aspects, the conductive material maybe copper, silver, gold, conductive alloys, or conductive polymer, andthe non-conductive material may be Kapton, ETFE, PTFE, non-conductivepolymer, or polyimide.

The conductive layers function as wires and form a return path for theUS sensor 260 and EM sensor 262, connecting the sensors to trackingdevice 160 and/or computing device 120. For example, in one embodiment,conductive layer 402 is connected to via 302, conductive layer 404 isconnected to via 304 of US sensor 260, and conductive layer 402 andconductive layer 404 are coupled to the EM sensor 262 through vias (notshown).

Since the US sensor 260 and EM sensor 262 are very thin, they have ahigh resistance, however, a low resistance is desired for the returnpath. In one embodiment, each conductive layer 402, 404, 406, 408 isprinted 360 degrees around the instrument 300 and along the length ofthe instrument 300 back to the proximal end in order to reduce theresistance on the return path.

As described above, one methodology for applying US sensors toinstruments is via printing directly on the instruments. FIG. 6 shows aprinting apparatus 600 that prints conductive material, non-conductivematerial, and piezoelectric material directly to the desired locationsof the instruments. The printing apparatus 600 includes a reservoir 610,a printing nozzle 620, and an actuating arm 630. The reservoir 610includes a first tank 640, which contains a conductive material or apiezoelectric material, and a second tank 650, which contains anon-conductive material. The printing apparatus 600 can print a circuiton any instrument 660, which can be locked into the distal end of theactuating arm 630. In an aspect, the printing apparatus may print asensor over a polymer.

A controller (not shown) of the printing apparatus 600 controls anactuating motor (not shown) to move the actuating arm 630. The actuatingmotor is fixedly connected to the proximal end of the actuating arm 630.The actuating motor can index forward and backward and rotate theactuating arm 630. In an aspect, the actuating motor may move thereservoir 610 while printing. For example, the actuating motor may indexforward or backward the reservoir 610 while rotating the actuating arm630. Still further, the reservoir 610 and instrument 660 may be heldmotionless while the printing nozzle 620, which is fluidly connected tothe reservoir 610, moves about the instrument 660. Further, combinationsof these techniques may be employed by those of skill in the art withoutdeparting from the scope of the present disclosure.

In an aspect, the printing may be started from the distal end of theinstrument 660 or the proximal end of the instrument 660. In a case whenthe printing is started from the distal end of the instrument 660, theactuating arm 630 indexes the instrument 660 forward so that theprinting nozzle 620 can print the conductive material toward theproximal end of the instrument 660. In another case when the printing isstarted from the proximal end of the instrument 660, the actuating arm630 indexes the instrument 660 backward so that the printing nozzle 620can print the conductive material toward the distal end of theinstrument 660. After completion of printing the non-conductivematerial, the printing nozzle 620 may print the conductive material orpiezoelectric material over the instrument 660 again. By repeating thesesteps, the instrument 660 may have several types of sensors.

FIG. 7 shows a method 700 of printing the conductive layers 402, 404,406, 408 which form the return paths for the US sensor 260 and EM sensor262 on a surface of the instrument 660. The method 700 starts fromsetting a counter N as zero in step 710. In step 720, the printer printsthe conductive material for the vias 302, 304 or for the electricalcontacts which couple to an external computing device or ultrasoundimage resolution device. In step 730, the printer prints a conductivematerial on the tube. While printing, in step 740, an indexing arm ofthe printer, which holds the tube, indexes forward or backward, androtates the tube.

In step 750, the printer prints the conductive material for anotherelectrical contact. The contacts printed in steps 710 and 750 are to beused to connect to wires which lead to and connect with an externalapparatus such as the tracking device 160 of FIG. 1 or an ultrasoundimage resolution device.

In step 760, the printer prints a non-conductive material to form anon-conductive film over the printed conductive material. While printingthe non-conductive material, in step 770, the actuating arm of theprinter indexes forward or backward and rotates in a direction reversefrom the direction of printing the conductive material. In this way, theprinted conductive material is insulated from or protected from otherenvironments.

In step 780, the counter N is incremented by one. In step 790, thecounter N is compared with a predetermined number of layers. If thecounter N is less than the predetermined number of layers, the method700 repeats steps 720 through 790. If the counter N is not less than thepredetermined number of layers, the method is ended.

Although embodiments have been described in detail with reference to theaccompanying drawings for the purpose of illustration and description,it is to be understood that the inventive processes and apparatus arenot to be construed as limited. It will be apparent to those of ordinaryskill in the art that various modifications to the foregoing embodimentsmay be made without departing from the scope of the disclosure.

What is claimed is:
 1. A medical instrument comprising: a catheter; aconductive layer printed circumferentially around at least a portion ofthe catheter; a nonconductive layer printed on top of the conductivelayer; an ultrasound sensor printed on a distal portion of thenonconductive layer, the ultrasound sensor adapted to transmit andreceive signals; at least one pair of vias formed in the conductivelayer and nonconductive layer enabling electrical connection of theultrasound sensor and the conductive layer; and a connector formed on aproximal end of the catheter for connection to an ultrasound imageresolution device.
 2. The medical instrument according to claim 1,further comprising an electromagnetic sensor disposed on a distalportion of the catheter.
 3. The medical instrument according to claim 2,further comprising a base non-conductive layer on the distal portion ofthe medical instrument on which the electromagnetic sensor is printed.4. The medical instrument according to claim 1, wherein the ultrasoundsensor comprises an array of ultrasound transducers.
 5. The medicalinstrument according to claim 4, wherein the ultrasound transducerscomprise of piezoelectric material.
 6. The medical instrument accordingto claim 5, wherein the ultrasound transducers further comprise ofsilicon diaphragms, wherein the piezoelectric material is printed on thesilicon diaphragms.
 7. The medical instrument according to claim 5,wherein the piezoelectric material is selected from the group consistingof perovskite phase lead zirconate titanate (PZT), quartz, leadtitanate, barium titanate, and polyvinylidene fluoride (PVDF).
 8. Themedical instrument according to claim 4, wherein the array of ultrasoundtransducers comprises printed parallel rows of ultrasound transducers.9. The medical instrument according to claim 1, wherein the medicalinstrument is selected from the group consisting of an extended workingchannel, a biopsy forceps, a biopsy brush, a biopsy needle, and amicrowave ablation probe.
 10. The medical instrument according to claim1, wherein the conductive layer is formed from a material selected fromthe group of copper, silver, gold, conductive alloys, and conductivepolymer.
 11. The medical instrument according to claim 1, furthercomprising an outer surface formed of a material selected from the groupconsisting of ETFE, PTFE, polyimide, and non-conductive polymer.
 12. Themedical instrument according to claim 1, wherein the ultrasound sensor,conductive layer, and the non-conductive layer are printed usingdrop-on-demand (DOD) or ink-jet printing.
 13. The medical instrumentaccording to claim 2, wherein the electromagnetic sensor is printed on adistal portion of the medical instrument.
 14. The medical instrumentaccording to claim 2, wherein the electromagnetic sensor includes atleast one pair of contacts electrically connected to the electromagneticsensor.
 15. The medical instrument according to claim 14, wherein atleast one pair of contacts is coupled to the conductive layer.
 16. Themedical instrument according to claim 15, wherein the conductive layeris connectable to a measurement device configured to sense an inducedelectrical signal based on a magnetic flux change of an electromagneticfield, wherein a location of the medical instrument in a coordinatesystem of the electromagnetic field is identified based on the inducedelectrical signal in the electromagnetic sensor.